THE GOAL OF THIS 1-YEAR STUDY IS TO EXTEND AND IMPROVE THE CONTINUITY OF SEA SURFACE SALINITY (SSS) SATELLITE DATA FROM NASA AQUARIUS MISSION TO NASA SOIL MOISTURE ACTIVE PASSIVE (SMAP) MISSION THUS SUPPORT NASA'S PROGRAM TO CONTINUE OCEAN SALINITY SCIENCE. AQUARIUS WAS NASA'S FIRST MISSION DEDICATED TO MEASURING SSS AND COLLECTED 45 MONTHS OF GLOBAL DATA UNTIL AN ELECTRICAL MALFUNCTION ON THE SATELLITE ENDED THE MISSION IN EARLY JUNE 2015. EARTH AND SPACE RESEARCH (ESR) TOOK THE LEADING ROLE FOR AQUARIUS SSS DATA VALIDATION AND ERROR ANALYSIS AND HAD WELL EXPERIENCE WITH THE AQUARIUS DATA QUALITY. TO ASSURE THE SALINITY CONTINUITY FROM THE SATELLITE OBSERVATIONS WE PROPOSE TO VALIDATE THE SATELLITE SSS VARIATIONS THROUGH SCIENTIFIC ANALYSIS. THE IDEA IS TO REPEAT THE SCIENTIFIC ANALYSIS THAT HAS BEEN DONE WITH AQUARIUS OBSERVATIONS TO DOCUMENT COMPARABLE SALINITY SIGNALS FOUND IN THE ONGOING SATELLITE SSS OBSERVATIONS. THE VALIDATION WILL ALSO ADDRESS SEA SURFACE DENSITY/SPICINESS WHICH IS CALCULATED FROM SMAP-SSS AND ANCILLARY SEA SURFACE TEMPERATURE DATA. IT IS ALSO OUR OBJECTIVE TO SUMMARIZE THE UNCERTAINTIES FOR SALINITY MEASUREMENTS THAT HAVE BEEN STUDIED BY DIFFERENT RESEARCH GROUPS. THE WORK WILL ADVANCE UNDERSTANDING OF THE ROLES OF UNCERTAINTIES IN CAUSING THE DIFFERENCES BETWEEN OBSERVED SSS AND REFERENCE SSS. IN THIS PROPOSAL WE PROPOSE TO: 1. ANALYZE AND COMPARE THE MEAN SALINITY FIELDS FROM AQUARIUS AND SMAP 2. EXPLORE THE SALINITY SIGNATURES IN AQUARIUS AND SMAP ON DIFFERENT TEMPORAL AND SPATIAL SCALES 3. SUPPORT THE ALGORITHMS AND THEIR IMPLEMENTATION FOR SATELLITE-DERIVED SEA SURFACE DENSITY AND SPICINESS DATA AND PERFORM COMPARATIVE ANALYSES WITH IN-SITU DATA 4. SUMMARIZE KNOWN UNCERTAINTIES FOR SALINITY MEASUREMENTS TO INFORM STATISTICAL ANALYSES